ABSTRACT

To elucidate the effects of nitrogen (N), phosphorus (P) and potassium (K) on cotton growth and yield, field studies with four N treatments (506, 402.5, 299 and 195.5 kg ha⁻¹ designated as N1, N2, N3 and N4, respectively) and four managements (M) of P and K application, designated as PK-M1 (total P and K applied at squaring stage (SS)), PK-M2 (25%:75% at SS and bloom-bolling stage (BS)), PK-M3 (50%:50% at each stage), PK-M4 (75%:25% at SS and BS) were conducted in 2018 and 2019. Results are shown in reproduction growth, PK-M3 under N treatments had the highest maximum biomass (K’) and fastest speed of biomass accumulation (Vmax), and N2PK-M3 obtained higher K’ and Vmax than others, followed by N3PK-M3. The average boll number, boll weight and yield in N2 were greater than others, and N3 with a decrease of 3.4–6.1% in average yield over N2. Although the yield in N3PK-M3 reduced by 1.4–1.5% compared to N2PK-M3 (losses about $8–32 per hectare), the fertilizer input decreased about $60–63 per hectare than N2PK-M3. Results suggest that 50% PK application ratio during SS and 50% during BS coapplied with proper reduced N application rate could compensate the yield loss by maintaining a higher level of reproduction biomass accumulation.

摘要

为了阐明氮 (N)、磷 (P) 和钾 (K) 对棉花生长和产量的影响，对四种 N 处理（506、402.5、299 和 195.5 kg ha ^-1分别指定为 N1、N2、N3 ）进行了田间研究和 N4）和 P 和 K 施用的四个管理（M），指定为 PK-M1（在开平方阶段施用的总 P 和 K（SS）），PK-M2（在 SS 和开花阶段施用 25％：75％） 2018 年和 2019 年进行了 PK-M3（每个阶段 50%：50%）、PK-M4（75%：25% 在 SS 和 BS）。结果显示在繁殖增长、PK N处理下-M3的最大生物量（K '）和生物量积累速度（Vmax）最快，N2PK-M3获得更高的K '和V最大比其他人，其次是N3PK-M3。N2的平均铃数、铃重和产量均大于其他，N3的平均产量比N2下降3.4-6.1%。尽管与 N2PK-M3 相比，N3PK-M3 的产量减少了 1.4-1.5%（每公顷损失约 8-32 美元），但肥料投入比 N2PK-M3 每公顷减少了约 60-63 美元。结果表明，SS 期间 50% 的 PK 施用率和 BS 期间 50% 的施用率与适当降低的 N 施用量共同施用可以通过维持更高水平的繁殖生物量积累来补偿产量损失。